// 4.使用Maybe 重写ex4， 不要有if语句
const fp = require('lodash/fp')
const { Maybe, Container } = require('./support')

let ex4 = n => {
    return Maybe.of(n).map(parseInt)
}

console.log(ex4(3));
console.log(ex4('a'));
console.log(ex4(null));
console.log(ex4(undefined));
